Many devices are known for effecting a reduction in the size of a particulate in a particulate-containing substance. One such device is disclosed in U.S. Pat. No. 4,684,072, assigned to the same assignee as is the present invention. The aforesaid patent and the prior art listed therein will reveal various structures that have been employed over the years to effect an agitation of the comminuting media to effect the desired result. Each of these various structures provides varying degrees of sheer forces and impact forces for effecting the desired reduction in size of the particulate.
It is frequently desirable to cause particle size reduction of a solid contained in a liquid. Liquids are frequently wanted and desired in the total product system. For example, liquids tend to replace undesirable gases held by the particle. Further, more uniform particle size distribution is obtainable with liquid additions and a desired reaction or bond may even be created. However, in continuous type mills, that is, mills wherein a product is continuously introduced into the comminuting vessel at one end and the comminuted mixture or product is removed at the opposite end, a strong desire has existed for many years in providing apparatus which would quickly process the product flowing therethrough so as to increase the productivity of the mill. However, the length of time that the product remains in the mill is directly related to the particle size of the particulate desired in the output mixture or product. Further, considerable energy is consumed during the period of time that the mill is in operation. Thus, the cost of energy per unit of product can be greatly diminished if the amount of product being processed through the mill can be substantially increased. It has been discovered that the construction of the rotor has a direct influence on the efficiency of the mill.
In addition to the subject matter disclosed in U.S. Pat. No. 4,684,072 mentioned above, Applicant also wishes to make of record U.S. Pat. Nos. 4,582,266 and 4,746,069, all of which are assigned to the same assignee as is the present invention. Reference to the aforesaid three patents is to be incorporated herein by reference.
In instances where a particulate is contained within a liquid, as the liquid and particulate move through the mill, there is a tendency on the part of the liquid and particulate to carry the comminuting media along therewith toward the outlet from the mill. As a result, and eventually, a majority of the media will have migrated toward and congregated around the outlet from the mill thereby making the mill operate inefficiently and consume a great deal of energy.
Accordingly, it is an object of this invention to provide a mill for continuously processing product, wherein the comminuting media is sufficiently agitated and with a minimum of friction occurring between the moving parts to achieve the desired amount of comminution of a particulate-containing product and without effecting a migration of the media toward the outlet end of the comminuting vessel.
It is a further object of the invention to provide a continuous type mill, namely, a mill wherein product is introduced at one end of the vessel and the comminuted mixture or product removed at the opposite end, wherein the comminuting media is sufficiently agitated and with a minimum of friction occurring between the moving parts to achieve the desired amount of comminution of a particulate-containing product and without effecting a migration of the media toward the outlet end of the comminuting vessel.
It is a further object of the invention to provide a rotor having structure thereon which causes the media to move upstream against the flow of the liquid and particulate moving through the comminuting vessel to counter the tendency of the liquid and particulate to carry the media toward the outlet end of the vessel.
It is a further object of the invention to provide a continuous type mill wherein the media is maintained evenly distributed throughout the length of the comminuting vessel even when liquid and particulate is flowing from the inlet end toward the outlet end.
It is a further object of this invention to provide a mill, as aforesaid, wherein an increase in the amount of the comminuted mixture or product is effected while simultaneously reducing the energy consumed in comminuting the product per unit of product produced.
It is a further object of this invention to provide a mill, as aforesaid, which is durably constructed and which will provide a generally maintenance-free operating characteristic.